Does WD40 remove car scratches? And nine other things we learned testing car scratch removers

We've been testing car scratch removers for the last three years from popular brands such as Autoglym, T-Cut, Turtle Wax and more, to see if they worked and which was the best.

We also tested WD-40 to see if it worked at hiding scratches – as the manufacturer and countless You Tubers claim

Here are 10 things to remember next time you tackle a troublesome car scratch.

1. WD-40 does work... sort of

WD-40 stops squeaks, loosens rusted parts, frees sticky mechanisms – but it also hides shallow scratches.

However, we found that it takes four applications to make a noticeable difference and it will wash away the next time you clean the car.

This makes WD-40 a temporary fix until you have time to get to one of the best car scratch removers we discovered through our testing.

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2. Most scratch removers only remove shallow scratches

There are three types of scratches that can affect a car panel:

• Shallow scratch A scratch to the clear coat
• Medium scratch A scratch through the clear coat and into the basecoat
• Deep scratch A scratch into the primer or to the metal of the car panel.

Most car scratch removers are designed to take care of shallow scratches, scuffs and swirl marks.

Some of the products we tested faded the appearance of medium scratches, but none of them worked on deep scratches. However, keep in mind that they don't claim to work on anything more than a shallow scratch. 

If you identify a deep scratch on your car, it may be time to turn to a professional. Depending on the level of damage, a bodywork repair shop will either be able to smooth it out or, if need be, replace the car panel.

Check out our Which? Trusted Traders mechanics for recommended professionals.

How to identify your scratch

If you spot a scratch on your car, but can't tell how deep it is by sight, use this easy method to identify it.

Pass your fingernail over the mark. If your fingernail gets caught, this is a medium scratch at least.

With deep scratches, you'll see the primer or metal itself showing through.

3. You don't always need to pay more

We tested a range of car scratch removers priced between £2.10 per 100ml (T-Cut Rapid Scratch Remover) and £11.36 per 100ml (Autoglym Complete Scratch Removal Kit).

While some pricier options did well in our tests, we found that you don't have to shell out more for a repair job you'll be happy with. We found a great-value car scratch remover that did a commendable job at a cheaper price.

4. Some repairs don't last long

We investigated whether the car scratch removers we tested would survive a hand wash after their application.

We applied the products, let them dry and then washed the panel five times with car shampoo.

For the majority of the products we tested, the scratches reappeared before the five washes were up:

• The WD-40 washed away with the first treatment
• The repairs from two car scratch removers only survived two washes
• Repairs from two other scratch removers survived three washes
• The repairs from the best product survived all five washes.

See the most reliable cars

5. Washing creates a better finish

Once you've used a car scratch remover that gives you good results, you may nonetheless be dismayed to find the area of bodywork you've worked on left with a bit of a haze.

This duller finish is nothing to worry about. Give your car a once-over with a good polish and you'll be that much happier with the end results.

Here are six mistakes to avoid when washing your car – and what to do instead

6. You shouldn't need extra tools 

Some car scratch removers can be used with an electric car polisher on deeper scratches. 

We tested the Halfords 110W Polisher on medium and deep scratches with three compatible car scratch removers. 

We found that using a polisher didn't do a significantly better job at removing these types of scratches compared to applying the products by hand with a microfibre cloth. 

If you have scratches that get into your paintwork, we'd recommend taking your car to a garage for a better result.

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7. Preparation is key

One thing we can't recommend highly enough is prepping the area you're going to work on with the car scratch removers.

By prepping, we mean washing the vehicle with car shampoo to make sure there's no lurking grit. If this isn't done there is a risk that rubbing a foam pad or microfibre cloth over the area, with grit or sand on it, could make the scratches worse.

8. Avoid using on a sunny day

Not all car scratch removers do well when applied in direct sunlight. If this is the case, they do say so in their instructions.

9. Take your time

We found many car scratch removers need more than one application to get rid of the shallow scratch.

10. Do a test run

Many of the scratch removers we tested suggest applying the product to a small out-of-the-way area first. This is to make sure it reacts well with your paint job.

It will say in the instructions if you need to do this.